code: def __propose(self, word_id):
      dart = rand() * (self.__prob_sum[word_id] + self.__beta_prior_sum)
      if dart < self.__prob_sum[word_id]:
          idx = self.__alias_tables[word_id].generate()
          topic = self.__topic_indexes[word_id][idx]
      else:
          topic = self.__beta_alias.generate()
      return topic
  
imports: import os
  import numpy
  from tqdm import tqdm
  from paddlehub.common.logger import logger
  from slda_webpage.document import LDADoc, SLDADoc, Token, Sentence
  from slda_webpage.vose_alias import VoseAlias
  from slda_webpage.util import rand, rand_k
label_desc: Use image node_id 11 for calling the MHSampler obj's underlying member method code with example usage: obj.__propose(word_id) and returns: topic